Most discussions on the extinction of the Pleistocene megafauna in southern South America depend on dates determined for deposits within which the bones were recovered. An analysis based on taxon-dates (Grayson, 1987), the majority of which are from recent work in the Ultima Esperanza region, Southern Chile, suggests that the chronological framework for the rest ofFuego-Patagonia needs to be revised. ln addition, some implications for the assessment of the model of Coevolutionary Disequilibrium are introduced.